Dates of Key Votes in Assam, West Bengal, Tamil Nadu and Kerala Announced

A polling official applies ink to a female voter's finger in state assembly elections Bihar on Nov. 5. Four more states will go to the polls this spring.

Diptendu DUTTA/Agence France-Presse/Getty Images

Four Indian states will go to the polls starting next month, the Election Commission of India announced Friday, as Prime Minister Narendra Modi’s party tries to expand its footprint beyond its traditional strongholds.

The elections will be held between April 4 and May 16, and votes counted on May 19, Chief Election Commissioner Nasim Zaidi announced at a news conference Friday.

In all, more than 170 million voters are expected to cast votes to elect representatives to the state assemblies, Mr. Zaidi said.

Elections in the north-eastern state of Assam, which is currently ruled by the Congress Party, will be held in two-phases on April 4 and April 11, while in eastern state of West Bengal it will be in six phases from April 4 to May 5.

The chief minister of West Bengal is currently Mamata Banerjee who leads the All India Trinamool Congress.

The southern states of Tamil Nadu and Kerala will vote on May 16, along with the union territory of Puducherry, a region largely governed by the federal government, Mr. Zaidi said.

For the first time, the Election Commission has decided to introduce an option to vote for none of the above using a symbol to indicate dissatisfaction with all the candidates, said Mr Zaidi.

Last year, Mr. Modi’s Bharatiya Janata Party suffered a defeat in a pivotal state election in Bihar, a political blow that poses a challenge for the government as it tries to move ahead with its economic agenda.

Winning seats in state elections is crucial because the local legislatures elect members to the upper house of Parliament, or Rajya Sabha, where Mr. Modi’s Bharatiya Janata Party lacks a majority.

Some key legislation, including the nationwide Goods and Services-Tax bill, have been languishing in the upper house for months amid disruption in parliamentary proceedings.